Baylor College of Medicine
Development of Biomarkers to Study Strial Development and Degeneration

The stria vascularis is a specialized tissue in the inner ear, localized in the lateral wall of the cochlea. This tissue generates endolymph, a special fluid that is rich in potassium and provides the driving force for the function of the sensory cells in the ear. Strial defects are implicated in many human syndromes involving profound hearing loss and are one of the main causes of presbycusis (age related hearing loss). In spite of its importance for normal hearing, we know very little about the development of the stria vascularis. The goal of this project is to identify the genes that are responsible for strial development, and that present the potential to restore or regenerate damaged stria vascularis in cases of both congenital or age related hearing loss.

Research Area: Stria Vascularis Atrophy/Development

Long Term Goal: To understand how the development of the stria vascularis and apply this knowledge towards the regeneration and/or repair of damaged stria vascularis in cases of congential defects or age related hearing loss.

University of Miami Miller School of Medicine
Deciphering the role of Slc22a4 in the development of stria vascularis, and to determine the effect of supplementation of its antioxidant substrate ergothioneine, on age-related hearing loss

Since mutations in the SLC22 gene family have been implicated in various pathological conditions, there has been a renewed interest in understanding their role in the maintenance of normal physiological functions of cells. SLC22A4 is ubiquitously expressed in the body and transports across the cellular plasma membrane various compounds, including acetylcholine and carnitine as well as the naturally occurring antioxidant ergothioneine (ERGO). In addition, SLC22A4 is abundantly expressed in the stria vascularis (SV), but its role in SV biology is not known.

This project will help in understanding how SLC22A4 contributes to SV development, atrophy, and dysfunction of the cochlea, leading to hearing loss. The project also aims to determine whether ERGO supplementation can prevent SV atrophy and ameliorate age-related hearing loss (presbycusis) in a mouse model.

Southern Illinois University School of Medicine
Cisplatin-induced oxidative stress down-regulates strial Na+/K+-ATPase and endocochlear potential

Cisplatin is a widely used chemotherapy treatment for various solid tumors. Unfortunately, its use sometimes results in permanent hearing loss. Understanding the pathophysiology of cisplatin ototoxicity (toxicity to the ear) is crucial for the development of novel treatments to combat this serious side effect.

Preliminary studies from our lab suggest that cisplatin appears to reduce the sodium/potassium activity of the cochlear fluid maintained by the stria vascularis, an important tissue in the inner ear, which leads to hearing damage. However, this suppressive effect by cisplatin may be restored through epigallocatechin gallate (EGCG), a green tea extract that is an antioxidant with anti-inflammatory properties. This project aims to investigate the potential of EGCG in the treatment of cisplatin-induced hearing loss.